A motion guide device, which is a mechanical element for guiding linear movement or curvilinear movement of a moving body such as a table and in which rolling elements such as rollers are interposed between guide portions, provides a smooth movement so that the motion guide device is used in various fields such as robots, machine tools, semiconductor and LCD manufacturing equipment, and medical equipment.
A linear guide, which is a type of motion guide device, includes a track rail mounted on a base and a moving block which is assembled to the track rail so as to be movable relative to one another and on which a moving body is mounted. The track rail is provided with a rolling element rolling surface extending in a longitudinal direction. The moving block is provided with a loaded rolling element rolling surface opposing the rolling element rolling surface and a rolling element circulation path for circulating rolling elements. The rolling elements are rollably interposed between the rolling element rolling surface of the track rail and the loaded rolling element rolling surface of the moving block. When the moving block moves linearly relative to the track rail, the rolling elements interposed between the track rail and the moving block perform a rolling movement and endlessly circulate through the rolling element circulation path.
In such a motion guide device, the rolling elements that endlessly circulate in line in the rolling element circulation path are required to perform a smooth rolling movement. This is because if the rolling elements do not endlessly circulate in an aligned state, for example if skew occurs in which the rolling element is inclined with respect to the normal axis of rotation, high-accuracy guiding movement is inhibited by causing wear on the rolling element and the rolling surface, for example, and this results in a short life. Accordingly, a conventional motion guide device is provided with a rolling element guide member along the entire length of a loaded rolling element rolling surface so as to guide the unloaded side of rolling elements that perform a rolling movement under load between a rolling element rolling surface and a loaded rolling element rolling surface. The rolling element guide member used in the conventional motion guide device is disclosed as a “guide member” in the following Patent Literature 1.